There will likely be two different parties. Last time I had around 10 people with me, we got most of the way to Dogg's Stockade knifing every zombie with our pen knives, and yet there were still people waiting on another leader. At that time, no leader showed up to take everyone, even though two voulenteered(And didn't deliver) so to avoid confusion, in advance I've designated temesia as the second group leader, so if my instance fills up, follow his.

To follow someone's instance: Press F2, and type that player's name. In my case, you'll type "imrinfected" and in the case of the second leader, you'll type "temesia". When people start dying, you can choose either party to move to, but the smaller party will merge with the larger one regardless. To do this, we'll keep in contact over steam chat, and if some of you can't enter it, the leader will explain how many slots are open in the other party to start the merge. Then, it's as simple as just entering the other party leader's name.

The game has a tendency to lag other aspects of the browser, so make sure you're in AFK mode(Inventory, picking up an item, looking at the map) if you must go to a different tab. This way you won't take any damage, and you won't die.

In the event of a disconnect of anyone, you're free to try to catch up with the main group after re-connecting. This goes for the party leader as well. If the leader does go missing, either through a disconnect or a death, someone else will be designated on-the-fly, or the whole group will maintain the same path hoping there are no conflicts.